Electrode spacing adjustment



'Jan. 7,-195 8' R. s. RINGLAND ET AL 2,8

' ELECTRODE} .SPACING ADJUSTMENT Filed Jan. 21; 1953 [/7 1/91? tars.

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2,819,421 ELECTRODE SPACING ADJUSTMENT Robert S. Ringland, Clarks Summit, Pa., and Robert P.

Watson, Schenectady, N. Y., assignors to General Electric Company, a corporation of New York Application January 21, 1953, Serial No. 332,406 6 Claims. (Cl. 313-146) The present invention relates to high frequency electric discharge devices and more particularly to improved electrode spacing adjustment means for such devices.

In the manufacture of high frequency electric discharge devices it is very diificult to maintain the dimensions of the various assembled parts within the limits required for maintaining the electrode spacings within the limits necessary to meet the specified electrical parameters. In order to overcome this diiliculty various structures providing for the adjustment of the electrode position after assembly of the device have been proposed. The present invention relates to an improved construction for this purpose which is simple and inexpensive at the same time very effective for its intended purpose.

Further objects and advantages of the present invention will become apparent as the following description proceeds, reference being had to the accompanying drawing'and its scope will be pointed out in the appended claims. In the drawing the single figure is an elevational view in section of an electric discharge device embodying our invention.

Referring now to the drawing, our invention is shown applied to a disk seal type of electric discharge device having planar electrodes. In this specific embodiment illustrated, the device includes an anode 1 sealed to one end of a grid-anode insulator 2 in the form of a ceramic cylinder. The anode includes a cylindrical terminal portion 3 and active planar portion 4 and an intermediate portion including a hollow cylindrical supporting portion 5 and a sealing portion 6 which is bonded insulator 2. Intermediate the portions 5 and 6 is a section 7 of reduced cross section which may be readily produced by grinding of the shaped anode.

An anode stud 8 is bonded to the outer surface of the planar portion 4 of cylindrical supporting portion 5 of the anode structure. This stud is drilled through the center as illustrated at 9 providing an evacuation passage for the discharge device. This passage is closed by a suitable tubulation 10. An anode radiator 11 which, as illustrated, may be machined out of a solid block of good heat conducting material, such as aluminum or copper, is received in threaded engagementwith the anode stud 8 and bears at its lower. edge on the anode member just outside of the section 7 of reduced cross section area through an intermediate pressure ring or washer 12. It is apparent that with this construction it is possible to adjust the position of the planar anode surface 4 and its position with respect to the adjacent electrode surface by rotational adjustment of the radiator 11. In order to lock the anode in its desired final position a body of solder 14 may be flowed into the opening in the radiator surrounding the tubulation 10. This solder flows in around the threads of the radiator and anode stud and locks the two in position. The solder also enhances the heat transfer from the anode structure to the radiator.

While the remainder of the electric discharge device to the ceramic the anode and extends beyond the tates atent may be of known construction we provide additional features which contribute to the ease with which the various electrode spacings are secured and retained during operation. As illustrated an annular grid terminal 15 of the device is bonded to the lower end of the gridanode insulator 2 and this terminal supports a collar 16 which is brazed to the grid terminal 15 near the lower edge thereof and supports a grid collar 17 at its upper end. A grid washer 18 to which are attached the parallel grid wire conductors 19 is supported from an inturned flange 17a at the upper end of collar 17. The collar 16 also is bonded to grid-to-cathode insulating cylinder 20. The lower end of insulating cylinder 20 is bonded to a cathode supporting cylinder 21, which is provided with an intermediate corrugation 22 for adjusting the position of the cathode assembly as will be described at a later point in the specification.

The cathode and heater assembly includes a generally cylindrical member 23 which fits within the cathode terminal 21 and is brazed thereto near the lower end thereof. The cathode disk 24 is supported from the upper end of the cathode cylinder 23 by means of a corrugated foil 25. The foil provides for a minimum transfer of heat from the cathode surface and the corrugations lend Strength and rigidity to the thin foil to give the cathode a more stable position, particularly if the device is subject to mechanical shock impact. This feature further contributes to the retention of the desired electrode spacings during operation of the device. In accordance with usual practice the cathode is provided with a cylindrical heat shield at which surrounds the heater element 27.

The terminals of the heater element are connected by suitable conductors 28 and 29 to heater terminal cup 36 and the cathode shell 23, respectively. A getter element 31 is also connected between conductor 29 and in addition conductor 32. Conductors 28 and 32 are sealed through a ceramic header 33 bonded within the cathode sleeve 23 by means of surrounding tubular sleeves 34. These sleeves 34 are bonded to the ceramic by a suitable metal-to-ceramic bonding process. Prior to bonding the sleeves to the ceramic, the conductors are brazed to the ends of these tubular members. A suitable insulating material 35 may be applied to the bottom of the heater terminal cup 30.

As will be readily apparent the position of the cathode with respect to the grid may be adjusted by the amount of crimping of the corrugation 22 that is formed in the side wall of cathode terminal 23.

In the foregoing detailed description, it will be apparent that our invention provides a very simple construction which utilizes the anode radiator in cooperation with a special anode construction to provide a very efiective and close adjustment of the anode-grid spacing, as a direct result of which, for example, a parameter such as the natural resonant frequency of the grid-anode circuit in its associated cavity may be held to much closer limits than heretofore practicable in the art.

While we have described and illustrated in particular embodiment of our invention, it will be apparent to those skilled in the art that changes and modifications may be made without departing from our invention in its broader aspects and we aim therefore in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric discharge device comprising a cup-like conductive member including a pair of cylindrical portions of different diameters connected by a flange-like portion and a planar portion extending across the end of the smaller of said cylindrical portions, a cylindrical insulatordisposed about the smaller portions, a sealbetweenoneend'of-saidinsulatorand'said flange-like portion of said member, said flange-like portion, including an annular section of reduced thickness relative to the general thicknessof-said conductivememher, said section of reducedthicknessbeing 'disposed in' wardly of said sealfor rendering saidplanarportion' positionally adjustable, a stud extending into saidsmaller of said cylindrical portions and secured to said planar portion, an enlarged member threadedly cngagingsaid stud and bearing on said flange-like portion at said seal for adjusting the position of said planar portion and minimizing transmission of shock to means for preventing relative rotationalmovement of said enlarged member for-locking said planar portion in an adjusted position.

2. An electric discharge device comprising a cup-like conductive member includinga pair of cylindrical portions of different diameters connectedby a flange-like portion and a planar portion extending-across the end of the smaller of said cylindrical portions, a'cylindrical insulator disposed about the smaller of said cylindrical portions, a seal between one end of said insulator and said flange-like portion of said member, said fiange like portion including an annular section ofreduced thickness relative to the generaltthickness of said conductive-member, said-section of, reduced thickness being disposed inwardly, of said seal'and adapted for rendering said planar portion ,positionally adjustable, a stud extending into said smaller of said. cylindrical portions and joined to said planar portion, an enlarged memberthreadedly engaging said stud and bearing on said flange-likeportion at said seal for adjusting the minimizing shock transmission to, said planar portion through said stud, a passage extending, longitudinally through said planar portion, said stud and saidienlarged member for exhausting said device, and. a quantity of solder material disposed in said passageinusaid. enlarged member for permanently securingsaid enlargedzmember to said stud following an adjustment and toenhancethe heat transfer therebetween.

3, An electric discharge device comprising a cup like conductive member including, afirst cylindrical portion adapted for serving as an electrical contact, a smaller second cylindrical portion connected to saidfirst portion by a flange-like portion and adapted. for supportingan anode comprising a planar portion extending across the end of said second cylindrical portion, a cylindrical insulator disposed about said second cylindrical portion, a seal between one end of portion, said flange-like portion including an annular. section of reduced thickness relative to said-cylindrical portions of said conductive member disposed inwardly of said seal and adapted for rendering said. planar portion positionally adjustable, a stud extendinginto saidsecond cylindrical portion and joined to said planar portion, an enlarged member threadedly engaging. said stud, a bearing washer disposed between said enlarged member and,

said fianged-like portion and seal, said. enlarged member bearing on said insulator through said flange-like portion seal. between one end ofsaid envelope section andsaid' said planar portion, andposition of saidplanarportion andsaid insulator and saidflange-like of said cylindrical 45 flanged upper portion, said electrode having an annular section of reducedthickness relative to" the thickness of both said bottom and flanged" upper portions and disposed therebetween for facilitating adjustable positioning of said bottom portion, a threaded stud bonded to said bottom portion, and a member enclosing and threadedly engaging the outer end of'said' stud and bearing on said flanged upper portion at said seal for etfectingupon turning thereofadjustment movements of' said planarbottom portion of; said electrode, said member being enlarged:

relative to said stud; and bottom portion to facilitate turning of said member andtoatford an increasedosurface area for dissipation of heat, conducted thereto from said electrode, the enclosure of'the end of said studby saidmemher and said bearing, of said member on such flanged upper port-ion being further eflective for minimizing any shock transmission to said bottom portion through said stud.

5. An electric discharge device comprisingan' annular insulator; a' cup-shaped anode having a bottom portion disposed in said insulator andcomprising an active area, an upper annular portion and an intermediate annular portion of reduced thickness relative'to' said'bottom and upper annular portions, a seal betweensaid upper annular portion ofsaid anode and the corresponding end of said insulator, threaded means secured'tosaid bottom portion, and a member of greater diameter than said threaded means and anode threadedly engaging said threaded meansand bearing on saidupper annular portion'ofsaid anode-at said seal for effecting upon turning thereof adjustment" movementsof said bottom portion, said reduced thickness of said intermediate annular portion' of said'anode facilitating said adjustment movements and minimizing stress atsaid seal during said adjustment'movements, saidmemberincluding a pluralityof finsfor facilitating gripping'thereof and affording anincreased surfaceareafor dissiptation of heat conducted thereto fromsaid electrode.

6. An electric discharge device comprisinga cup-shaped anode'including an elongated outer cylindrical portion, an elongated inner cylindrical portion of smaller diameter than saidouter cylindrical portion and reentrant therein and a connecting portion reentrant in said outercylindrical portion and joining said inner and outer portions, said-connecting portion having an annular section of substantially reduced thickness relative to said outer and innerportions, a cylindricalinsulator surrounding said inner portion and reentrant in said" outer portion, a seal between the reentrant'portion' of said'insulator and said anode at said-connectingportion, said inner portion of said anode having a-bottom surface comprisingthe active area thereof; a stud bonded to said active area, and a member threadedly engaging said stud andbearing on said connecting portions of said anode, over said seal for beingefiective when turned to adjust the position of said active area, said member being large relative to said stud and anode to'atford leverage and thus facilitate turning thereof.

ReferencesCitcdin the file of this patent UNITED STATES PATENTS 2,108,640 Bieling Feb. 15, 1938 2,407,974 Clifford Sept 24, 1946 2,446,269 Drieschman Aug. 3, 1948 2,473,827 Spencer June 21, 1949 2,720,608 Wihtol Oct. 11, 1955 2,722,624 Doolittle Nov. 1, 1955 FOREIGN PATENTS 583,177 Great Britain Dec. 11, 1946 

